This invention relates to a flat-type compact cosmetic case for face powder, rouge, eye shadow, powder puff, etc., having a push button for disengaging the engagement between the case body and the lid.
A compact cosmetic case for face powder, rouge and the like, generally, has a pan-like case body and a substantially flat lid which is pivotally connected to the rear portion of the case body. This type of case usually has a fastening mechanism such that the free front end of the lid is unfastenably fastened to the front portion of the case body by means of two engaging projections when the lid is brought into its closed position. Among the various conventional fastening mechanisms are included disengaging operation members such as push buttons for disengaging projections so that the lid can be opened. To be prepared for the following lid-closing action, those disengaging operation members must be brought back to their initial positions after being released from pressing force.
An example of the conventional case having a push button is disclosed in Japanese Utility Model Application Laid-Open No. sho 60-44708. As shown in FIG. 1 and 2, a case body 1 of this compact cosmetic case has a recess 2 formed in its front wall portion 1a. This recess 2 is defined by an end surface 2a, a bottom surface 2b and opposite side surfaces 2c, and opens to the top and front faces of the front wall portion 1a. The end surface 2a of the recess 2 is provided with a projection 3 having its upper surface 3a tapering forwards. As shown in FIG. 2, the opposite end surfaces 2c of the recess 2 are provided with guide grooves 4 extending in a direction perpendicular to the end surface 2a. The depth of each guide groove 4 decreases gradually from its front to its rear end. A push button 6 is slidably received in the recess 2 for movement along the guide grooves 4.
The push button 6 includes: a sliding plate 6a adapted to be directly pressed by operator; two resilient strips 6b projecting from the inner surface of the sliding plate 6a; and a pivoting leaf 6d pivotally connected, for upward and downward movement, to the inner surface of the plate 6a through a hinge portion 6c. The resilient strips 6b fit slidably in the guide grooves 4 respectively. The free end of the pivoting leaf 6d is in contact with the slope 3a of the projection 3. As shown in FIG. 1, when the lid 5 is in its closed position, a engaging projection 5a of the lid 5 is in contact with the pivoting leaf 6d and is in engagement with a engaging projection 1b which is formed on the end surface 2a. When the push button 6 is pressed backward, the pivoting leaf 6d is pivoted upward under the guidance of the slope 3a. Then, the pivoting leaf 6d pushes the engaging projection 5a upward, causing the engaging projection 5a to be disengaged from the engaging projection 1b. Also, when the push button 6 is pressed, the resilient strips 6b are bent sideward, as shown in FIG. 2, under the guidance of the guide grooves 4. Therefore, the push button 6 is urged forward by the reaction force due to the bend of the resilient strips 6b. Consequently, button 6 is brought forward into its initial position when released from the pressing force.
However in the aforementioned compact cosmetic case, there arises the following problems: The front wall portion 1a of the case body 1 must be of a relatively large thickness T.sub.1 since it is required to have a recess 2 deep enough to receive both the projection 3 and the pivoting leaf 6d. In other words, the thick front wall portion 1a restricts the length L.sub.1 of the hollow 1c to a relatively small size. Furthermore, since the resilient strips 6b are flexed sidewards, only the forward component of the reaction force is exerted on the push button 6 in moving the push button 6 back to its initial position. That is to say, in the aforementioned case, the entire reaction force due to the bend of the resilient strips 6b is not efficiently utilized.
Another example of the conventional compact cosmetic case is disclosed in Japanese Utility Model Application Laid-Open No. sho 61-160812. As shown in FIG. 3 and 4, the end surface 7a of a recess 10 of this case does not have a projection, and thus it is much easier for this cosmetic case to have the front wall portion of a relatively small thickness than for the previously mentioned conventional case. Instead of the projection, this case has an urging leaf 9e inclined to the bottom surface 7c of the recess 10. This urging leaf 9e is connected to the lower edge of a sliding plate 9a through a resilient strip 9d, and is in contact with the end surface 7a of the recess 10. As shown in FIG. 3, when a lid 8 is in its closed position, an engaging projection 8b of the lid 8 is adjoined to the free end of the urging leaf 9e and is in engagement with an engaging projection 7b which is formed on the end surface 7a of the recess 10. When the push button 9 is pressed backward as shown in FIG. 4, the urging leaf 9e is pivoted upward under the guidance of the end surface 7a, whereby the engaging projection 8b is pushed upward and is disengaged from the engaging projection 7b. The resilient strip 9d also serves as means for generating biasing force when the push button 9 is pressed. When the button 9 is pressed, the resilient strip 9d is elastically deformed, and thus, by the reaction force due to the deformation of the resilient strip 9d, the push button 9 is urged forward.
However in the above-described case, since only the resilient strip 9d (the thickness of which is substantially thinner than the urging leaf 9e) is used as means for generating the urging force, the push button of the case is prevented from having a sufficient durability. For example, a small plastic deformation in the resilient strip 9d due to elastic fatigue can greatly reduce the urging force of the resilient strip 9d so that the push button is not able to return to its initial position.